The 6-year-old daughter of Kanye and Kim Kardashian West is a protective big sister over her baby brother Psalm, 3 months, in a series of photographs her mom shared to Instagram on Tuesday morning, holding him in her lap as their brother Saint, 3½, sits next to them on a couch.

As the slideshow goes on, North becomes increasingly warier of Saint, who throws up a peace sign in the second snapshot while his big sister looks down.

The third image is where things get hilariously heated, with Kardashian West’s two oldest children exchanging adorably menacing expressions as baby Psalm simply peers at the camera.

“It was going so good…. swipe ➡️ 😂,” the Keeping Up with the Kardashians star, 38, captioned her fun post.

Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Parents newsletter.

Missing from the memorable sibling photo was the couple’s second-youngest child, daughter Chicago. The 19-month-old has been hanging out in the Bahamas this week with her mom and aunt Khloé Kardashian, plus Kardashian’s daughter True, 16 months.

Kim, Kanye, North, Saint, Chicago and Psalm West’s Cutest Pics

In a photo gallery Kardashian shared to Instagram on Monday, True — outfitted in a leopard-print swimsuit by NATAYAKIM — was sporting a sweet pair of white shades as she sat next to Chicago, who was wearing a cute black-and-white outfit with a lace trim.

After posting snaps that showed the BFF cousins drinking from cups of water, the Revenge Body host shared three images of them digging into bags of chips — for Chicago, Cheetos Puffs, and for True, Sensible Portions’ Garden Veggie Straws.

The KKW Beauty mogul and West, 42, recently took a family trip to Japan, with their two oldest children in tow — and North used the opportunity to show off the fact that she is quite the worldly style maven.

A photo gallery shared by Kardashian West on Aug. 11 showed her oldest child rocking colorful ensembles complete with bold accessories, like a pink ruffled top and floral-patterned skirt over fishnet leggings, the latter of which were covered in flower appliqués.

Another snapshot saw North wearing feather-adorned kitten heels paired with athletic pants and a denim jacket. In subsequent images, the little girl sported tie-dye shirts, light-wash jeans, purple sweatpants, hoodies, a feathered top and more, carrying a variety of fun purses and backpacks.

“My Northie girl is the ultimate fashionista! She comes with me to fabric stores and picks out what she likes and for our Japan trip I let her style herself,” Kardashian West proudly captioned her post. “I should have let her style me too lol. She loves it. She’s having fun and I am so happy she’s so expressive. 💅🏼👽👘👑🌊🍬”